300
Milk kept past the expiration date often spoils,
tastes sour, and develops stringy curds. This
can be explained by which of the following?
(A) Fermentation produces ethanol and fibrous
by-products.
(B) Yeasts form citric acid, which causes the
yeast cells to form long chains.
(C) Bacteria produce lactic acid, which lowers
the pH and denatures the milk proteins.
(D) The Krebs cycle is converted to the Calvin
cycle.
(E) The production of fatty acid raises the
temperature and polymerizes lactose.
What is
(C) Bacteria produce lactic acid, which lowers
the pH and denatures the milk proteins.